<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            margin: 10px auto;
            height: 20vh;
            max-width: 800px;
            
            background-color: red;
            border: 2px solid #333;
        }
    </style>
</head>
<body>
<div>
<span></span>
</div>
</body>
</html>